SKIN CANCER (MELANOMA) - GENERAL
SKIN CANCER (MELANOMAS) CAUSES SYMPTOMS EXAMINATIONS TREATMENTS
Melanoma is one of the forms of skin cancer. It develops in melanocytes or pigment cells. For convenience, we will use the terms skin cancer and melanoma in the singular. But there are different kinds, and even with similar illnesses each person has specific peculiarities.
LEARN MORE HERE ABOUT SKIN CANCER (NON-MELANOMA)
Skin anatomy
Our skin is made up of three layers. The outer layer is called the epidermis, the middle layer is called the dermis, and the lower layer is called the subcutaneous connective tissue or hypodermis.
The epidermis is mainly made up of two types of cells: basal cells and squamous cells. In addition, there are pigment cells, melanocytes, in the epidermis. Basal cells in the deep layer of the epidermis are able to divide. This is where new skin cells are formed. Over a period of around a month, these new cells migrate upwards and, at the same time, change shape. At first they are round or oval, then they become more angular and later they flatten out (squamous cells).
The dermis is made up of connective tissue, also called supporting tissue. It includes: sweat glands (which produce sweat), hair follicles associated with sebaceous glands, blood and lymphatic vessels, as well as nerve endings.
The hypodermis primarily serves as a support and is made up mostly of fatty tissue.
The skin
The functions of our skin
It protects our body, for example against infections and ultraviolet (UV) rays.
It allows us to perceive signals coming from our environment: the cutaneous nerves transmit painful, sensitive and thermal stimuli to the brain which transforms these stimuli into sensations.
Finally, the skin plays a big role in regulating body temperature, the sweat glands of the skin largely contributing to this regulation.
Skin cancer (melanoma) in numbers
The infographic below has been produced based on figures from the Cancer Registry. The figures are transposed there in the form of graphs representing the number of new cases per year, the age groups most affected and the number of deaths due to this type of cancer.
Despite prevention campaigns, the number of melanomas continues to increase each year. Although melanoma very rarely occurs before puberty, it is one of those cancers which, compared to other types of cancer, is more common in people under the age of 60. It is mainly caused by excessive exposure to UV rays (natural or artificial).
Types of melanoma
Melanoma literally means black tumor. This type of skin cancer appears in melanocytes or pigment cells. Normal melanocytes are present in a disseminated form throughout the skin. They can also be gathered in small clusters and then form pigmented spots, like moles (moles).
We talk about melanoma when, in a place of the skin, the pigment cells transform into cancer cells. The resulting malignant tumor will present itself as a pigmented spot that grows or enlarges, changes color etc.
Where are melanomas located?
Melanoma can appear in an existing mole or an isolated pigment cell in an area of "healthy" skin, without a pre-existing pigmented spot. Melanoma can develop anywhere on the skin. In women, they appear a little more frequently on the legs, in men on the trunk. Areas covered with hair, such as the scalp, can also be affected.
Exceptionally, melanoma can appear in the lining of an organ. A mucous membrane is a thin layer of tissue that lines the body cavities. These melanomas can affect the mouth, nasal cavities and throat, as well as the vagina and anus. Melanoma sometimes also occurs in the lining of the eyelids and in the eye itself.
Skin cancer metastases
Just like any other cancer, skin cancer can metastasize elsewhere in the body. By the lymphatic route, tumor cells reach the lymph nodes in the neck, armpits or groin (depending on the location of the original tumor) and multiply there to give rise to lymph node metastases.
Cancer cells can also spread through the bloodstream to other places in the body, for example to the lungs.
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